3/17/2016
TKS 4406 Material Technology I
Alumunium (Non-Ferrous Metal)
Dr.Eng. Achfas Zacoeb, ST., MT. Department of Civil Engineering Faculty of Engineering University of Brawijaya
Geology of Bauxite Bauxite ore is the most abundant element found in the earth's crust, although the word bauxite is used to describe any material that contains more than 32 percent alumina.
A Bauxite rock with impurities
http://www.hs.wisd.org/ddaughenbaugh/Pictures/ alcoa_aluminum_smelter_and_mine.htm
1
3/17/2016
Geology of Bauxite
(cont’d)
Dislodged
rock particulates in areas of heavy rainfall percolate down to the water table, where aluminum silicate compounds accumulate and pressure causes them to join together.
In
this form the compounds are what we consider bauxite.
Geology of Bauxite There
(cont’d)
are three main structural types of bauxite: Gibbsite Böhmite Diaspore
Each
of these three types of bauxite has different characteristics that make them more or less desirable for mining purposes.
2
3/17/2016
Geology of Bauxite Gibbsite
(cont’d)
has a maximum alumina content of
65.4%. Böhmite and diaspore both have a maximum alumina content of 85%. Of the bauxites currently being mined, the dominant form is gibbsite, followed by a mixture of gibbsite and böhmite. The main impurities are compounds of iron, silicon and titanium.
Geology of Bauxite
(cont’d)
The
three structural differences of Bauxite can be further categorized into two groups, the difference being in the water content of each: Monohydrates Trihydrates
3
3/17/2016
Geology of Bauxite
(cont’d)
Trihydrates
are comprised of gibbsite and böhmite and are found in Latin America and Caribbean areas.
Deposits
of desirable bauxite occur as flat layers lying near the surface and may cover many miles - the average thickness of these layers is 4-6 meters.
History of Bauxite Use Bauxite
was used long before it was ever refined into aluminum. In Guyana it was used to build homes with the so-called "brown-mud" that would later be called bauxite. These deposits were also used to make pots and plates, along with using it as a plaster for homes.
4
3/17/2016
History of Bauxite Use
(cont’d)
It
was not until 1825 that western cultures devised a way to make aluminum from bauxite. The Danish Chemist, Hans Oerstad was able to isolate a small amount of aluminum from bauxite.
Over
the next few decades new procedures were introduced that lowered the cost of aluminum, however it was still used only for jewelry purposes.
History of Bauxite Use
(cont’d)
It
was not until 1886 that the Hall-Heroult electrolytic process, which is used to make aluminum from alumina, was discovered.
In
1889 Karl Bayer introduced the Bayer process of extracting mass amounts of alumina from bauxite .
5
3/17/2016
History of Bauxite Use
(cont’d)
Four
to six tons of bauxite are needed to produce two tons of alumina which in turn produces one ton of aluminum.
In
1998, the total area mined for bauxite was 1591 hectares (3929.77 acres) of which 80% was wildlife habitat, 175 hectares (432.25 acres) was tropical rainforest and 577 hectares (1425.19 acres) possessed important fauna species.
Alumina Production According to Persaud, in the Bayer Alumina reduction process: the bauxite is first ground and mixed with chemicals (sodium hydroxide/caustic soda, lime). Then it is pumped into huge pressure containers and heated, after which more chemicals (lime to regenerate caustic soda) are added, and hydrated alumina crystallizes from the solution after being seeded with other (trihydrate alumina) crystals. These crystals are then washed and heated at very high temperatures to drive off the moisture until a white powder remains. This is the alumina or aluminum oxide.
6
3/17/2016
Alumina Production
(cont’d)
The OSHA (Occupational Safety and Health Administration) filed Material Safety Data Sheet for Caustic Soda (Sodium Hydroxide-NaOH) lists it as a highly reactive alkaloid dangerous to human health.
Alumina Production
(cont’d)
Effects of exposure to Caustic Soda: ACUTE OVEREXPOSURE: Corrosive to all body tissues with which it comes in contact. CHRONIC OVEREXPOSURE: Chronic local effect may consist of multiple areas of superficial destruction of the skin or of primary irritant dermatitis. Inhalation of dust, spray or mist may result in varying degrees of irritation or damage to the respiratory tract tissues and an increased susceptibility to respiratory illness.
7
3/17/2016
Alumina Production
(cont’d)
Courtesy of: http://www.hs.wisd.org/ddaughenbaugh/Pictures/alcoa_aluminum_smelter_and_mine.htm
The World's Bauxite Sources
Courtesy of http://www.hs.wisd.org/ddaughenbaugh/Pictures/alcoa_aluminum_smelter_and_mine.htm
8
3/17/2016
Benefits of Aluminium Advantages: Corrosion resistance Strength Formability Recyclability Appearance Hygiene Light weight
Benefits of Aluminium
(cont’d)
Light
weight vs High strenght Density 1/3 lower than iron or copper Tensile strenght 70-700 MPa, toughness remains down to -200°C Enhanced corrosion resistance Base metal is protected by spontaneously formed Al2O3-layer Passive layer is spontaneously repaired in suitable conditions
9
3/17/2016
Benefits of Aluminium
(cont’d)
Conductivity
Good electrical- and thermal conductivity Good light and heat radiation reflectivity Machinability Suitable for facing, cutting and drilling Connectivity Suitable for welding, soldering, riveting and gluing
Benefits of Aluminium
(cont’d)
Economical
production Production of recycled Al requires only 5% of the energy needed for primary Al Recyclability Hygienic & Non-toxic Formability Product range from heavy plates to thin foil Suitable for extrusion, deep drawing (cans) and forged products Suitable for rod filling and mould casting
10
3/17/2016
Features
Temperature range 0o - 200oC Melting temperature 650oC pH range 2 - 8,5
Limitations: Poor wear resistance Sensitive to surface scratches Low high temperature strenght Low creep strenght Low fatigue strenght Price variations
Applications in Construction
Facades (1 mm AW 3003 panels)
Roofing (AW 3105 panels)
11
3/17/2016
Applications in Construction (cont’d)
Profiles, Fittings, Walkways, Shades, Frames, etc.
Most Common Grades EN AW
1050A EN AW 3005 EN AW 3105 EN AW 5086 EB AW 5754 EN AW 6082 (Extruded products) (European Standard)
12
3/17/2016
Most Common Grades
(cont’d)
Most Common Grades
(cont’d)
13
3/17/2016
Aluminium di Indonesia Aluminium terbuat dari 66% bauksit dan 33% tanah liat (aluminium oksida dari P. Bintan di Propinsi Kepulauan Riau).
Aluminium di Indonesia (lanjut)
Klasifikasi aluminium ada 2 (dua) kelas: Kelas Aluminium yang dapat dikeraskan dengan perlakuan panas (heat treatable) seperti : Al kelas 2XXX, 6XXX dan 7XXX sedangkan kelas yang non-heat treatable seperti 1XXX, 3XXX dan 5XXX, untuk kelas ini hanya dapat dikeraskan dengan cara deformasi dingin (cold work).
14
3/17/2016
Aluminium di Indonesia (lanjut)
Aluminium termasuk golongan logam ringan yang dapat dicor, digilas, ditarik, ditekan dan dilas. Aluminium akan rusak oleh kapur, gips, adukan semen dan beton, sehingga perlu adanya perlindungan khusus bagi elemen konstruksi yang terbuat dari aluminium. Aluminium, selain profil untuk jendela dan sebagainya, banyak digunakan sebagai lembaran papak atau aluminium gelombang.
Aluminium di Indonesia (lanjut)
Sifat-sifat aluminium dipengaruhi oleh logamlogam lain sehingga terbentuk aluminium campuran, antara lain : Nama Dagang
Campuran
Penggunaan
Antikorodal (Ac)
Aluminium (Al), Magnesium(Mg), Silisium (Si)
Alat perlengkapan pintu, jendela dan mebel
Silafont (Sf)
Aluminium (Al), Silisium (Si)
Permukaan pemasak pada kompor listrik
Alufont (Af)
Aluminium (Al), Tembaga (Cu), Titan (Ti)
Pembangunan kendaraan, kapal dan pesawat terbang.
Aluman (Am)
Aluminium (Al), Mangan (Mn)
Aluminium lembaran
Peraluman (Pe)
Aluminium (Al), Magnesium (Mg)
Aluminium lembaran hiasan dengan anode oksidasi
15
3/17/2016
Aluminium di Indonesia (lanjut)
Nama Dagang
Campuran
Penggunaan
Extrudal (Ed)
Aluminium (Al), Magnesium(Mg), Silisium (Si)
Aluminium lembaran hiasan dengan anode oksidasi
Avoinal (Av)
Aluminium (Al), Tembaga (Ti), Magnesium (Mg)
Industri kendaraan, kapal dan pesawat terbang
Zinkalamunium (Zn)
Aluminium (Al), Seng (Zn)
Aluminium lembaran untuk penutup atap.
Thanks for the attention and Success for your study!
16
